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Alefacept Effective in Treating Patients With Psoriasis
Psoriasis is a chronic, inflammatory skin disorder. According to the article, scientific and clinical evidence suggests that T cells, specialized cells involved in the immune response, are involved in psoriasis. Skin severely affected by psoriasis has been observed to have high levels of CD4+ and CD8+ memory T cells (two types of T cells). Previous experimental studies have shown that elimination of T cells reduced the severity of psoriasis.
Kenneth B. Gordon, M.D., of Loyola University Medical Center, Maywood, Ill., and colleagues examined the effects of intravenous alefacept on the severity of psoriasis and T cell levels.
The researchers conducted a phase 3 clinical trial involving 553 patients with chronic psoriasis. The patients were randomized into one of three groups. Each group participated in a 12 week course of treatment (or placebo), followed by a twelve week period of observation without any drugs. Then, for eligible patients, there was a second 12 week course of treatment (or placebo) and another 12 weeks of observation.
Group 1 – 7.5 milligrams of intravenous alefacept each week for both courses
Group 2 – 7.5 milligrams intravenous alefacept each week in the first course, and 7.5 milligrams intravenous placebo each week for the second course
Group 3 – 7.5 milligrams intravenous placebo each week in the first course, and 7.5 milligrams intravenous alefacept each week in the second course
The researchers found that one or two courses of alefacept reduced CD4+ and CD8+ memory T cell counts. Patients who received alefacept in course 1 with the largest decrease in T cell counts experienced the greatest reduction in disease severity. The benefits of treatment lasted longest in participants who had the greatest reduction in CD4+ and CD8+ T cell counts.
"This phase 3 trial indicates that the reduction in levels of circulating memory T-cell subsets with alefacept treatment correlates to improvement in psoriasis and suggests a relationship between the length of response to alefacept and alterations in the memory T-cell population," the authors write.
Arch Dermatol. 2003;139:1563-1570. Available post-embargo at https://jamanetwork.com/journals/jamadermatology
Editor's Note: This study was funded by Biogen, Inc., Cambridge, Mass.
Source: The Archives of Dermatology